I think Bitcoin is almost big enough that SM can soon come out in the open and not fear reprisal. Any publicity gained from attacking [him] as they did Assange would gain more publicity for Bitcoin and would help legitimize it. There is nothing illegal about Bitcoin and any fear shown toward SM would show the strength of Bitcoin. It probably won't be long before we know the face behind Bitcoin.
To what advantage for him/her?
If Satoshi wasn't interested enough in adulation to reveal his identity years ago; I don't see why he/she would be now.
If anything, the big stack of bitcoins Satoshi holds will be more useful to him if his identity remains secret. That only becomes more true the bigger bitcoin gets.
My guess is that his identity will never be known; or if it is, it won't be for a long time, possibly after his/our deaths.